Study of landfill site suitability and sensitivity analysis using GIS-FAHP for solid waste management: a case study in Ranchi, India

Introduction Globally, urbanising cities are generating increasing amounts of municipal solid waste. Despite recycling and energy recovery being more sustainable waste management practices, landfilling remains the preferred disposal method. This requires scientific and environmentally conscious approaches to identify landfills. Methodology This study addresses this necessity by developing a GIS-MCDM framework with sensitivity analysis to identify potential landfills in Ranchi with an operational life of 20 years. GIS was employed to generate maps and buffer zones for the 11 criteria. Buckley’s geometric mean FAHP method was employed to derive weights for 11 criteria using a pairwise comparison matrix and fuzzy triangular scales. Simultaneously, population growth was predicted using the geometric increase method, enabling the calculation of the minimum landfill area. A landfill suitability map was produced by overlaying the maps with the derived weights. Result According to the findings, 1.6% of the research area was unsuitable for landfilling, followed by 25.5% less suitable, 70% moderately suitable, and 3% most suitable, identifying 614 most suitable sites. For a landfill lifetime of 20 years, the minimum area was found to be 27 ha, and the number of most suitable sites was reduced to 191, of which 35 sites lay between 20 km and 25 km from Ranchi airport. Finally, based on land-use suitability, 4 sites were identified as potential landfill sites. Model output validation was performed using receiver operating characteristic (ROC) curves, selecting 70 points across various locations in the district. The area under the curve (AUC) was 0.91, validating the spatial results. The sensitivity analysis revealed that distance from settlement was most sensitive to changes in the suitability class of cells in the evaluation map. Discussion This research provides a holistic framework for sustainable landfill site selection that policymakers and researchers can replicate to ensure environmentally sound waste management.